Pond Boss Forums AERATION Should I aerate? Aeration essay contest

Entries must describe the benefits of aeration for small ponds in 75 words or less. (No big words please)

The winning contestant shall receive all the fish in all of the worlds oceans.

I would enter this contest but my pond can't hold all of the fish in all of the worlds oceans, besides they would die without salt water anyway.

Ok, well I'll take a stab at it anyway....

Aeration will help to ensure that your fish never contract Pneumonoultramicroscopicsilicovolcanoconiosis.

Oops I've been disqualified since I used the largest word in the English language (at least according to the Oxford English Dictionary).

I could tell you want it means but then I'd have to kill you.

So much for my planned use of "antidisestablishmentarianism".

Small ponds generally don't benefit from wave action like larger bodies of water do.

Consequently, small water bodies need to rely on plants for oxygen in an unaerated system.

Because of this, you are totally at the mercy of the daily wax and wane of the plant communities daily cycle of photosynthesis and respiration.

Aeration is necessary to counteract the dreaded low oxygen situations that occur every morning right before sunrise.

71 words...oops, that makes 73....D'OH!, that makes 76. Dang! I'm disqualified.

Yeh, and I was thinking of that one from the "Sound of Music" with Doris Day.

We have a winner in Bruce. He took the words right outta my mouse; but much more eloquently.
He should know about needing O2, with those brutes he grows.

Thanks, burger, but as many of you know, most of my experience comes from killing fish instead of growing them.

Thank you Bruce, that's what I was hoping for. Your entry made it easier for me to concisely explain aeration to my neighbor.

I hereby proclaim, by the power invested in me by internet anonymity, that on this day all the fishes of all the seas of the planet Earth now are the sole (don't go there) property of the noble Dr. Bruce "Big Gills" Condello.

You may now kiss the fishes.

*Edited for syntax

Bruce will you please explain the difference between circulation and aeration systems and how they both work.

Bruce i think I now get it but a bottom diffuser doesn't work the way I thought it did. Now I also understand how a circulator can have such a big impact.

Danger: Repeat post...


Let's talk a little about what aeration really is.

There has historically been a misunderstanding about what it means to aerate a pond. When I strike up a conversation with a pond neophyte they will commonly talk about aeration being a priority for their new pond.

The most common comments are that a pond needs aeration so the fish can breathe, and that the best ways to do this are with a fountain or a diffuser. Bubbles equal oxygen, right?

Not so fast...

Let's start with some simple water physics.

Things diffuse into and dissolve into water. Water is the universal solvent. Air dissolves into water.

The percentage of oxygen in air is 20.9476 %

Oxygen will move across the "air/water interface" (remember this term ) until it reaches saturation.

Saturation is the measure of how much oxygen water will hold at a certain temperature before it starts to spit oxygen back out into the atmosphere.

Salinity also affects how much oxygen it takes to saturate water. Higher salinity means water holds less oxygen.

If water is less than saturated it wants to take up oxygen out of the atmosphere and this is, in turn, good for fish.

When you put a diffuser on the bottom of your pond and bubbles start to come out of it, the fish really aren't interested in gulping the bubbles. What they really want is the pure oxygen that's diffusing out of the bubble across the "air/water interface".

In high school physics class we learned that lots of smaller bubbles have a lot greater surface area than a few big bubbles. That's why a good diffuser makes the bubbles as tiny as possible. Lots more little bubbles means more surface area, which means more "air/water interface", which means more oxygen diffused into the water for the fishies to use.

Make sure to get a good diffuser. This helps. But what a bottom diffuser aerator system really does is brings a big column of water up from the bottom so that the unoxygenated bottom water gets a chance to gulp some oxygen from the gigantic "air/water interface" at the surface of the pond. This produces a lot more usable oxygen than the bubbles themselves.

How else can we increase this "air/water interface"?

Waves are a good way. I'm sure it is intuitively correct to all of you that a wavy surface has a lot more surface area than a flat surface. Big ponds and lakes usually have more wave action. This means they are not as susceptible to universally low oxygen levels as a pond. That's why we rarely need to oxygenate a 200 acre body of water. There are lots of 200 acre water bodies that would benefit from aeration--just not as many critical oxygen crashes as there would be with a one acre system.

Waves are good.

What's another way of increasing the "air/water interface"?

How about circulation? If you stir water by using, for example, a circulator, the oxygen is constantly jumping into the water from the atmosphere to saturation, then that surface layer is pulled down and replaced by another layer of less than saturated water, which then becomes saturated, again and again and again.

This brings up an important point.

If you have a pond that is completely devoid of oxygen because of an algae crash or some other such disaster, the water at the very, very, very surface is actually saturated with oxygen. That's why fish pipe at the surface to try to survive. The problem is that the saturated layer is only about one molecule thick. Trust me on this one. I found this out from a college instructor who told me that this isn't enough for a fish to survive. Everything below this is robbed of oxygen so the fish probably won't make it. That fish either needs plants to be producing oxygen from below, or enough oxygen mixing from above to adequately support their life processes.

That water either needs mixed from the big vortex formed by a nice bottom diffuser system, or a circulator or a thriving plant community.

Bruce remember the oxygen is the green tank and the nitrous is the blue tank and people need the green tank.

Bruce I just bought a 1hp 120v circulator with a control panel. It should arrive on Tuesday. Do you have any reccomendations on placement or setting it up? How many hours a day should I run it?

You feed your fish, right?

I put my circulator right in front of the feeder. The fish spend a lot of time there anyway, so they can become familiar with the more higly oxygenated area that they can use in times of stress..

The other good thing is that regardless of the wind, my circulator spews the feed straight out in every direction. The wind never blows the feed to shore, and the area with the most activity is the most aerated.

I've also noticed that the fish that don't eat pellets mill around near the circulator, and I think they may be utilizing small invertebrates that get caught up in the current.

That 1 hp is really gonna crank out the water!

Bruce thanks for all your help. I should get it on Tuesday and install it on Friday. So should I put the timer to stay on all the time?

I have two feeders going now and I'm installing a third one this weekend.

Initially I'd say yes, to leave it on all the time, but maybe to run it just at night during times of the year that the water is cooler and you're feeding less, or not at all.

I created a grid to mount the circulator to the pond's bottom. It's a very simple aluminum template, with four sleeves drilled into it. Then we took four steel poles and drove them into the pond's bottom, leaving about five inches sticking out. This way the circulator slides up and down with the changing water level. The DO has been at virtual saturation since it was installed.



Keep in mind everybody that the monthly energy bill can be pretty high for these systems. I think that 1 hp puppy will consume about ten cents an hour of electricity.

Is that some Mountain Lightnin in the picture? Bruce why did you have to engineer such an impressive mounting platform. Why not just use the mooring ropes that came with it? The guy I bought mine from said it was supplied with mooring ropes and to attach them to the bottom with concrete blocks. I have a new problem. I didn't have electricity at the dock sunday so I had the electrician come out and he told me moles or gophers were eating the plastic around the underground wire. He fixed the problem but he said they would probably attack it again until I put conduit around it. I buried this wire myself and it is about 800 feet long. To dig up that much wire gives me a headache just thinking about it. I guess there is much hard work to being a pond boss. I also had a long discussion today with a guy selling kosco circulators. He told me that they absolutely do not add oxygen to your pond and he was a biologist to prove it. He also said getting information off of the internet was a very bad idea.

That might be the nuttiest thing I've ever heard in my life.

How does he think an airlift aerator works? All it does is increase the air/water interface so oxygen can diffuse into the water from the atmosphere.

Run an experiment sometime. Buy a bucket of 24 fathead minnows. Put them in a warm place and wait until they start "piping", or sipping oxygen at the surface. Then take you index finger and start to gently swirl the surface in a circular motion. The fatheads will happily return back to their normal preferred position. You can keep them alive this way until your finger wears out. Now I'm sure your "biologist" will tell you that your finger doesn't add oxygen to the water-----and technically he's right---but by turning the water, the atmospheric oxygen diffuses into the water more quickly than your two dozen fatheads can use it up. This is pretty simple stuff. I wonder if I should send him the graph of dissolved oxygen readings that I created using a $6,000 Isco water
sampler last summer.

What a goof.

Maybe he should tell the shrimp farmers in Thailand that provide all of their oxygen with circulation that their shrimp should be dying.

"Shhhh, don't tell the shrimp they should be dead." :rolleyes:

The reason why airlifts are so nice is that they use the fact that oxygen is lighter than water to create the circulating effect. This is why their efficiency can be so good. But really a diffuser/bubbler system is circulating too. It's just on a different plane. Bubbles go up, water goes with them, and water around the column has to drop to takes it's place. A circulator uses a motor to "push" the water sideways, but the concept is the same. Bring as much low oxygen water to the surface, as often as possible and let physics do the work.

How is being a biologist related to fluid science? Please offer this gentleman an invitation to join the forum.

I politely said thank you and hung up on him and ended up not buying anything from him. The red dock is where my electricity is located. The other dock has the second fish feeder on it. Anyone that doesn't think a turtle trap works look at the over 100 in this picture. This is one of the stocker bass I put in around january.[IMGhttp://i112.photobucket.com/albums/n165/james12_04/IMG_1237.jpg[/IMG]p

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